//图片上传预览    IE是用了滤镜。
					function previewImage(file) {
						var MAXWIDTH = 260;
						var MAXHEIGHT = 180;
						var div = $('#preview').get(0);
						if (file.files && file.files[0]) {
							div.innerHTML = '<img id=imghead>';
							var img = document.getElementById('imghead');
							img.onload = function() {
								var rect = clacImgZoomParam(MAXWIDTH, MAXHEIGHT, img.offsetWidth, img.offsetHeight);
								img.width = rect.width;
								img.height = rect.height;
								img.style.marginTop = rect.top + 'px';
							}
							var reader = new FileReader();
							reader.onload = function(evt) {
								img.src = evt.target.result;
							}
							reader.readAsDataURL(file.files[0]);
						} else //兼容IE
						{
							var sFilter = 'filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(sizingMethod=scale,src="';
							file.select();
							var src = document.selection.createRange().text;
							div.innerHTML = '<img id=imghead>';
							var img = document.getElementById('imghead');
							img.filters.item('DXImageTransform.Microsoft.AlphaImageLoader').src = src;
							var rect = clacImgZoomParam(MAXWIDTH, MAXHEIGHT, img.offsetWidth, img.offsetHeight);
							status = ('rect:' + rect.top + ',' + rect.left + ',' + rect.width + ',' + rect.height);
							div.innerHTML = "<div id=divhead style='width:" + rect.width + "px;height:" + rect.height + "px;margin-top:" + rect.top + "px;" + sFilter + src + "\"'></div>";
						}
					}
		
					function clacImgZoomParam(maxWidth, maxHeight, width, height) {
						var param = {
							top: 0,
							left: 0,
							width: width,
							height: height
						};
						if (width > maxWidth || height > maxHeight) {
							rateWidth = width / maxWidth;
							rateHeight = height / maxHeight;
							if (rateWidth > rateHeight) {
								param.width = maxWidth;
								param.height = Math.round(height / rateWidth);
							} else {
								param.width = Math.round(width / rateHeight);
								param.height = maxHeight;
							}
						}
						param.left = Math.round((maxWidth - param.width) / 2);
						param.top = Math.round((maxHeight - param.height) / 2);
						return param;
					}